1. Field of the Invention:
This invention relates to a closed circuit television apparatus such as a supervisory system, and more particularly to a closed circuit television apparatus for remotely controlling the operation and functions of television cameras.
2. Description of the Prior Art:
Generally, in a closed circuit television apparatus such as a supervisory system, at each of different places to be observed a remotely controllable television camera is located, and at a central supervisory station a monitor for receiving video signals from the individual television cameras, a controlling device or operating device for controlling the operation and functions of the television cameras, and a switching circuit for selecting one of the television cameras to be connected to the controlling device and the monitor are located. The operation and functions of each television camera, such as make-and-break of a power, make-and-break of a heater, make-and-break of a wiper, tilting, panning, focusing and zooming, is controlled by a control signal supplied from a controlling device and each television camera transmits video signals to the central supervisory station.
However, since the conventional closed circuit television apparatus requires cables for transmitting the video signals and cables for transmitting the control signals, such many cables must be built between the central supervisory station and the individual television camera, thus resulting in a complicated and expensive system.